Broadband energy-time entangled photon-pair source based on a fiber-pigtailed PPLN waveguide [Invited]
Peng Wu, Yunru Fan, Hao Yu, Guangwei Deng, You Wang, Hai‐Zhi Song, Hao Li, Lixing You, Guang‐Can Guo, Qiang Zhou · Chinese Optics Letters · 2025
We report a broadband energy-time entangled photon-pair source based on a fiber-pigtailed periodically poled lithium niobate (PPLN) waveguide, designed for applications in the quantum secure network.Utilizing the spontaneous parametric down-conversion nonlinear optical process, the source generates entangled photon pairs within a wavelength range of 64 nm in the telecom band at a pump wavelength of 770.3 nm.Photon pairs from eight paired International Telecommunication Union (ITU) channels are selected, and their correlation and entanglement properties are characterized.The measured coincidence counts of photon pairs from eight paired ITU channels are larger than 152.9 kHz when the coincidence-to-accidental ratios are greater than 260.Entanglement properties are measured through two-photon interference in the Franson interferometer, with all visibilities of interference curves exceeding 98.13%.Our demonstration provides a broadband energy-time entangled photon-pair source, contributing to the development of a large-scale quantum secure network.